A. Field of the Invention
The invention relates to endoscopic surgical tools and methods. More particularly, the invention relates to endoscopic methods and devices having robotic capabilities.
B. State of the Art
Endoscopic surgery is widely practiced throughout the world today and its acceptance is growing rapidly. In general, endoscopic surgery involves one or more incisions made by trocars where trocar tubes are left in place so that endoscopic surgical tools may be inserted through the tubes. A camera or magnifying lens is often inserted through one trocar tube, while a cutter, dissector, or other surgical instrument is inserted through another trocar tub for purposes of manipulating and/or cutting the internal organ. Sometimes it is desirable to have several trocar tubes in place at once in order to receive several surgical instruments. In this manner, organ or tissue may be grasped with one surgical instrument, and simultaneously may be cut with another surgical instrument; all under view of the surgeon via the camera.
By 1996, it is expected that more than two million additional endosurgeries will be performed per year that, in 1990, were done via open surgery (MedPRO Month, I:12, p.178). The advantages of endoscopic surgery are clear in that it is less invasive, less traumatic and recovery is typically quicker. As a result, many new tools and devices for use in endosurgery are introduced every year. For example, it is now known how to use a powered microsurgical tool for intravascular surgery such as that disclosed in U.S. Pat. No. 5,059,203 to Husted. Husted teaches a miniature rotatable work wheel having a cutting blade that is integrally formed with a drive hub and axle and mounted for rotation at the end of a casing member. The casing member is a multi-lumen tube. A single monofilament drive line is looped around the drive hub and extends through separate lumens of the multi-lumen tube to a source of drive power. The drive hub also has a cupped cross section for inhibiting the monofilament drive line from riding off the hub. A drag load is applied to the payout end of the monofilament drive line close to the drive hub. The rotating wheel may be a cutting wheel or an abrading wheel, and is used primarily for opening occluded blood vessels.
Endoscopic surgical tools with articulate end effectors are also now known. U.S. Pat. No. 4,880,015 to Nierman discloses a biopsy forceps for use in a flexible fiberoptic bronchoscope. Nierman's forceps are provided with an increased range of operability when obtaining tissue samples due to a hinge joint located between the forceps grippers and the cable from which the grippers extend.
Meanwhile, the art of robotics is also developing rapidly. while originally conceived of in fiction, modern robotics involves discrete specialized applications often in the area-of manufacturing, but also in the areas of research and development and where hazardous environments must be traversed. In this latter application, robotics often involves electro-mechanically activated articulate members emulating human arms and hands which are operated by an encoding device responsive to the articulation of human arms and hands of an practitioner. Known encoding devices generally include an exoskeleton or sleeve which fits over the human arm of the practitioner. The encoding sleeve is provided with joints corresponding to the joints in a human arm and one or more ring bearings all of which translate motion by the human arm of the practitioner into mechanical, electrical, or electromechanical signals. These signals generated by the encoder are then transmitted to a robotic arm which responds to the signals from the encoder. The robotic arm is usually moved by servo motors which are located in the robotic arm joints. The object of this type of arrangement is to provide a mechanical or electromechanical arm which will mimic the movements of the human arm of an practitioner. Robotic arms are also usually provided with some type of gripper which is activated by hand movement of the practitioner. These types of robotic arm arrangements are most often used in hazardous environments such as the handling of nuclear materials, the disarming of bombs, and in space exploration (where the signals from the encoder to the robotic arm are transmitted over long distance by radio waves).
Early robotic arms were clumsy and useful only for completing gross tasks such as lifting, pouring, twisting and the like. It was difficult to obtain an arrangement of encoder and robot arm which had the responsiveness of a human arm. This difficulty stemmed from the quality of the servo motors, the difficulty in encoding the articulations of the human arm, and the lack of feedback to the encoder. State of the art robotic arms, however, have overcome many of the difficulties encountered by the early robotic arms. It is now possible to construct robotic arms which have a wide range of movements closely mimicking the articulations of the human arm and which provide feedback to the encoder to more correctly mimic the movements of the practitioner. State of the art robotic arms are capable of performing sophisticated tasks such as welding, soldering, sewing, manipulation of a variety of tools, handling of small pieces, etc. Encoders are now commonly provided with feedback mechanisms which offer the practitioner varying resistance corresponding to the resistance encountered by the robotic arm.
Recent developments in robotics and in telecommunications have created a new art called "virtual presence" In virtual presence, an encoder with audio, video, and tactile feedback is worn by a human "participant" and is connected through a transceiver to a robotic apparatus having audio, video and tactile sensors at a distant location. The object of virtual presence is to allow the human participant to act and feel as if the participant is actually present at the distant location. Virtual presence technology has been applied in the aerospace industry for controlling remote space probes, in oceanography for controlling deep sea probes, and in environmental sciences for the handling of hazardous materials.
While endoscopic surgery is ever gaining in acceptance, it is still often more difficult to perform than open surgery insofar as the surgeon must view the surgical site through an endoscope or a camera rather than viewing it directly through a large incision. In this sense, endosurgery using video cameras is similar to virtual presence since the participant (in this case the surgeon) does not see the surgical site directly, but rather sees a virtual representation of the surgical site on a television screen. However, while virtual presence virtually places the participant in a distant scene, in endosurgery, the surgeon must reach into the televised scene using tools which function unlike human arms and hands. In state of the art endosurgery the surgeon is limited to tasks for which tools are available, while in open surgery the surgeon can still apply the wide range of articulation available to human arms and hands. Nevertheless, in either type of surgery, the surgeon must be within arm's length of the patient.
Despite advances in robotics, the robotic techniques have heretofore never been used in endoscopic surgical instruments or procedures, probably because the robotic instruments are relatively large and the endoscopic instruments are relatively tiny.